Hi there,
It might be because you entered an invalid zone name on the previous page.
This error can be generated when you enter a zone name that doesn’t match the domain of the master DNS server you specify.
This thread might also be Helpful
https://social.technet.microsoft.com/Forums/azure/en-US/6975567d-2f73-4e34-a5de-1e9309287611/the-server-with-this-ip-address-is-not-authoritative-for-the-required-zone?forum=winserverDS
If the reply is helpful, please Upvote and Accept it as an answer